Tri-phase photonic crystal emitter for thermophotovoltaic systems

Abstract

Thermophotovoltaics (TPVs) are devices that convert thermal radiation into electricity using a low-bandgap photovoltaic (PV) cell. While the theoretical efficiency can approach the Carnot limit, designing a TPV selective emitter that is spectrally matched with the PV cell's bandgap and is stable at high temperatures is critical for achieving high-efficiency systems. Photonic crystal (PhC) emitters can provide excellent spectral control, but prior experimental designs lack the thermal stability required for high-performance TPVs. In this study, a tri-phase PhC emitter design is proposed and optimized. The tri-phase design introduces an additional material in one of the alternating layers of an existing 1D PhC emitter, potentially stabilizing it at high temperatures. BaZrO3 is introduced in the CeO2 layers of a CeO2/MgO PhC emitter. Stanford Stratified Structure Solver (S4) is used to model the emittance of multiple tri-phase PhC variations. The parameter for optimization is the spectral efficiency of the emitter. The structure with the highest spectral efficiency is only 0.02% less efficient than the original design. The structure with the lowest spectral efficiency is only 0.28% less efficient. Therefore, any tri-phase variation can be applied to existing PhC emitters without compromising on their spectral efficiency. Without the need for manufacturing specific parameters, the tri-phase PhC can be an inexpensive emitter for real world applications that may improve thermal stability without compromising on the spectral efficiency, making the practical applications of TPVs feasible.